The present invention relates to a video encoding/decoding system, and is applicable, for example, to a video encoding/decoding system with failure detection function.
Driver support function and automated driving function for vehicles have been put into practice in recent years. In a system including an in-vehicle camera and an image analysis device for the purpose of detecting obstacles or other purposes, the resolution of the images to be handled has been increased to achieve a high precision. Because of this, digital video transmission using image compression techniques has been widely used. A high level of safety is required for the driver support function and automated driving function. Thus, it is necessary to use a method that can detect failure in the video encoding device, the transmission path of the compressed image, and the video decoding device. There have been proposed failure detection techniques, for example, as disclosed in Japanese Unexamined Patent Application Publication Nos. 2006-148430 (Patent Document 1) and 2008-546338 (Patent Document 2), as well as in the corresponding U.S. Pat. No. 8,457,199 (Patent Document 3).
Patent Document 1 describes the following: “The technique is an image recording device for compressing a digitally converted video signal in an image compression part 6, extending data recoded in a hard disk recording part 11, and outputting the extended data. The image recording device includes an ROM 9 for recoding a reference data as well as a test data generation part 3, in which the data of the test data generation part 3 is compressed and stored in the image compression part 6. The compressed test data is compared with the reference data. The data of the test data generation part 3 is stored in an RAM 10 to compress and store in the image compression part 6. Then, the reference data of the ROM 9 and the test data compressed in the RAM 10 are compared with each other to determine whether the data is normal or not, in order to perform self-diagnosis to check the fact that abnormality occurred in either the hard disk recording part 11 or the image compression part 6.”
Patent Document 2 describes the following technique: “In a transmitter, a video signal is encoded by generating a differential signal (in 2), showing the difference between the transmission image and the predicted image based on the image that is stored and partially decoded. The differential signal is decoded to generate a new partially decoded image. The transmitter also generates a check signal, such as CRC, which is used as a function of the partially decoded image. A receiver decodes the differential signal and generates a decoded image. Then, the receiver compares the decoded image with the check signal. If the two do not match, the receiver generates an error signal.”